Selective switch



May 23,1944. w. H. T. HOLDEN 2,349,279

' 'SELECTIVE SWITCH Filed Maron 2, 1943 s sheets-sheet 1 /NVE/VTOR BV WH 7.' HOLDEN v ATTORNEY May 23, 1944. w. H. T. HOLDEN.

Y SELECTIVE SWITCH f 3 sheets-shew 2 Filed March 2, 1943 HUNDREDS ATTORNEY May 23, 1944- w. H. T. HOLDEN 2,349,279

SELECTVE SWITCH Filed March 2, 1943 5 sheets-Sheet 5 96 97 aa a9 f l I l No.9 TENS. Y

a@ K F/G. 3

No.4 TENS NOOTENS 00a |09.` 902 902 00| |0| v 90| 90| ooo |00 90o' 90o No.0 N0.| No.9 No.9 J HUND. HUND. HUND. HUND.

I/VI/E/VTOR l/L/ H 7.' HOLDEN A T TOR/VE V Patented May 23, 1944 UNITED SELECTIVE SWITCH William T. Holden, Woodside, N. Y., assignorto Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application Marchffl, 1943, Serial No. 477,718

4 Claims This invention relates. to selective switches and particularly to switches of the kind 'employed in communication and other electrical systems.

The objects are .to increase the capacity and also the efciency of selective switches, to simplify their structure and operation, and to effect other improvements therein.

Switches of "the crossbar type havebeen designed heretoforelhaving capacities of a 'thousand l.points andmore. Where these large capacities are desired it is usually necessarir to provide at leastv three sets of magnets for actuating the bars toselect and operate a desired set of contacts, and it is also generally necessary to keep at .leastone of the magnets in an operated condition throughoutr the period the selected set of contacts are closed. Attempts have 'been made to avoid the current drain in'these large-capacity switches byfreeing all of the magnets as vsoon as they have operated theidesired Contact set. This end; however,'has been realized-in the past only'at the expense of an vadditional setY of magnets and structural complications as well.y

In accordance with the present invention advantages .are'obtained over 'these'prior ydevices bymeans ofacrossbarswitch of large capacity in which only three sets of magnets are required for actuating the 'switch bars to select and operate 'the contact sets 'and in which the magnets participating in the operation of a desired set of contacts .may be deenergized forthwith since they 4arel no longer required to maintain rthe operated contacts in their closed condition. More specifically, the hold` bars, which cooperate with the :select bars, are so `designed that vthe selected set of contacts is `,operated by the restoring Inovement .of ahold ,bar from its off-normal to its normal position; moreover, the contact-'set thus selected and operatedis maintained in the operated conditionby the hold bar after it has restored yto its normal position;

The selection of 'a'desired set of contacts in a switch'Y of this character, having a capacity `of one thousand contactsets, for example, is accomplished by energizingone of ten irst select magnets to prepare a .group of one hundred select fingers for cooperation with respective hold bars, energizing one of 'ten `second Aselect magnets for positioning the. corresponding select ngers with respect to a .groupY of ten of said hold bars,

energizing one of tenpperating. magnets to move a single hold bar against the tension of a retractile spring ,fromit's normal position into its actuated position where it is operatively engaged .by a single `oneof 'the selectngers preparedcby the operation of said first select magnet,v deenergizing` the operating magnet to yper mit the `retractile spring to restoresaid hold bar toitsnormal position. for Vthepurpose of operating the-desired setof 'contactsand nally deenergizing the first and second select magnets. Thus it is possible to select and operate yany set of contacts by briefly energizing the appropriate pair of select magnets and the appropriate operating magnet, the retractile spring of the particular hold bar involved in the operation serving to restore and retain the bar in its normal position to maintain the selected contacts closed as long asthe connectionis desired, all three of the magnets being deenergized at once and remaining deenergized throughout the connection to avoidthe consumption of electrical'energy. To eiiect the release of any operated set vof contacts, it is only necessary to energize momentarily. one of the select magnets and one 0f 'the operating magnets.

A feature of the invention is an off-normal contact arrangement for a switch of this character in which a set of off-normal contacts and an off-normal bar are provided for each of the hold bars of the switch. The switch hold bars and the oli-normal bars are arranged to cooperate with the select fingers of the select bars in such a manner that the operation of any switch hold bar to effect the Aclosure of any one of the sets of switch contacts associated therewith also causes the operation of the associated off-normal bar to close the individual set of olf-normal contacts.

These and other features of the invention will be described more fully in the following specii cation.

In the drawings accompanying the specification:

Fig. l is a simplied diagram illustrating the principles of operation of the switch;

Fig. 2 is a perspective view showing the essential structure of a switch incorporating the features of the invention; and

Fig. 3 shows one convenient numbering plan for the contact sets.

Because of the wide variety of details that may enter into the construction of crossbar switches andv since these switches in their numerous types are already well-known in the art, it is believed to be sufficient to illustrate in the present disclosure only those essential features of structure and operation which are necessary to a clear understanding of the invention. And'it will be understood that the particular embodiment disclosed is to a large extent diagrammatic and conventional and is not intended to limit the scopeof the invention, which obviously may be applied to a large variety of switch structures.

As explained above, the switch disclosed herein is one of large capacity, that is to say, a switch having too many contact sets `for convenient selection by the usual two sets of operating bars and magnets. Although the invention is not to be limited to any particular capacity, it is convenient to describe and illustrate it in connection with a switch capable of selectively operating any one of a thousand sets of switching contacts. Referring to Figs. 1 and 3, it will be seen that the thousand sets of contacts are arranged in a eld comprising ten equal switching units or groups. These contacts are coordinately arranged in vertical and horizontal rows, and the ten vertical rows correspond to the ten hundreds groups of the thousand. These ten hundreds groups are served by a group of ten select bars 5I). Three of these vertical rows or hundreds groups are illustrated in Fig. 1: the No. 0 hundreds group, which is served by the No. select bar I and the associated select magnet 2;A the No. 6 hundreds group, which is served by the No. 6 select bar 3 and the associated magnet 4; and the No. 9 hundreds group, which is served by the No. 9 select bar 5 and the associated select magnet 6. The remaining seven hundreds groups have been omitted for the sake of clearness.

The ten hundreds groups of contacts are divided into ten tens groups, three of these tens groups being illustrated, the No. 0, No. 4 and No. 9 groups, 1, 8 and 9, respectively. These tens groups are served by a second set of select bars 60 and associated magnets, there being a bar and associated magnet for each of the successive tens groups. For example, the No. 0 select bar IIJ and its associated select magnet II serve the No, 0 group of contacts 1, the No. 4 select bar I2 and associated magnet I3 serve the No. 4 tens group 8, and the No. 9 select bar I4 and associated select magnet I5 serve the No. 9 tens group 9.

Each of the i'lrst or hundreds select bars 2, 4, 6, is provided with one hundred flexible select ngers, one for each set of contacts in the corresponding hundreds group. These flexible select iingers cooperate with notched hold bars which are respectively individual to the horizontal rows or units groups of contact sets. The hold bars are arranged in groups 22, 23, 24, corresponding to the tens groups of switching contacts. For example,the hold bar 25 is individual to the No. 0 units group'of contacts in the tens group 1 and is provided with ten notches 26, 21, 2B, cooperating with the corresponding select fingers 29, 30, 3I. Similarly, the hold bar 32 is individual to the No. 6 units group of contacts in the tens group 1 and is provided with notches cooperating with the corresponding select fingers on the hundreds select bars. And the same is true of the remaining hold bars of group 22 and of the other groups. The hold bars 25, 32, 33, etc., are maintained in their normal positions (the position shown in Fig. 1) by means of retractile springs 34, 35, 36, etc.

The second or tens select bars 6I! are also provided with flexible select fingers for cooperation with the hold bars. For example, the No. 0 select bar Ill has ten select fingers 31, 38, 39, which cooperate respectively with the notches 40, 4I, 42, in the hold bars of the No. 0 tens group 22. The No. 4 select bar I2 is provided with ten select fingers 43, 44, 45, which cooperate respectively with the notches 46, 41. 48, in the hold bars of the No. 4 tens group 23 and the same is true of the remaining eight select bars including the tenth or No.9 bar I4.

The switch is further provided with ten groups of operate bars 5|, 52, 53', one group for each tens group of contacts, each group including a bar for each group of units in the tens group. For example, the operate bars 54, 55, 56, of the group 5I are individual respectively to the No, 0, N0. 6

and No. 9 units groups of contacts and are associated respectively with the corresponding hold bars 25, 32,33. The operate bars 54, 55, 56, of the group l5I are provided with notches with which the respective select fingers 31, 38, 39 cooperate. The same is true of the operate bars in each of the other nine groups including those in the groups 52 and 53 illustrated. These operate bars are controlled by the third set of ten magnets, the operate magnets I6, I8, 20. The No. 0 operate magnet I6, for example, controls the ten operate bars 54, 51, 58, which correspond to the No. 0 units groups of contacts in the ten tens groups. For this purpose the magnet I6 is provided with a drawbar I1 which is mechanically coupled to the ten operate bars 54, 5158. The draw-bar I1 is held in its normal position to maintain the operate bars in their normal positions by means of a retractle spring 59. The No. 6 operate magnet I8 controls the ten operate bars serving the No. 6 units groups through the associated drawbar I9 and its mechanical linkages, and the draw-bar I9 is maintained in its normal position by the retractile spring 6I. Similarly the remaining operate magnets, including the No. 9 operate magnet 20, control the associated operate bars through corresponding draw-bars and mechanical linkages.

Sets of off-normal contacts are provided for the switch and associated individually with thev respective horizontal rows of switch contacts. These off-normal contactsare operated by ofinormal bars which are individual to and arranged to cooperate with the corresponding hold bars. For example, the off-normal contact sets 62, 63,

64, associated respectively with the No. 0, No. 6v

and No. 9 horizontal rows in the group 1 are operated by the individual off-normal bars 65, 66, 61, which .in turn are associated with the hold bars 25, 32 and 33. These off-normal bars are moved to their contact-closing positions and are held in these positions by the corresponding hold bars. To this end the off-normal bars are provided with notches for receiving the actuated select iingers on the vertical bars.

A detailed description will now be given of the operation of the switch structure shown in Fig. 2. For this purpose it may be assumed that the set of switching contacts 68 is to be operated. According to the assumed numbering plan this set of contacts bears thle designation 990. That is to say, it occurs in the No. 9 hundreds group, in the No. 9 tens group and in the No. 0

units group. By means of appropriate controlling circuits the magnet 6 is energized to pull the select bar 5 downwardly. The downward movement of the bar 5 flexes the select fingers 3l, 69, 10 (of which there are one hundred), against the upper edges of the corresponding hold bars 25, 33, 1I. It will be noted that the notches 23, 12, 13, in the hold bars are displaced slightly to the right of the corresponding select ngers when the bars are in their normally retracted positions. For example, if the bar 1I is at this time in its normal position, as indicated in the drawings, the finger 10, on being flexed downwardly by the operated select bar 5, engages the upper edge of the bar 1I and does not enter the notch 13, and the same is true of all other select fingers ilexed by the select bar 5.

Assume next that the circuits are arranged to energize the select magnet I5 shortly after the energization of magnet 6. The energization of magnet I5 pulls the select bar I4 downwardly and causes the ten corresponding select fingers* 14,1: .15, 4to .enter-the .notches in.the.-coriespondingipairsgofxoperateiand hold bars, provided. these:`V

bars vare rat .the `time. .in '.theirl normal. positions. Toa illustrate, the: operatecbar 58 '.randfthe asso.-`

ciated :hold bar :1I are vprovided withY notches r1b".A

and11,respectively.,'which are in alignmentiwith.

the vselect finger 14 when these bai-snare in :their r normal' positions; hence, the: downwardf; move# ment of the bar I4 causes: the select iingen114 to;

enter both notches I6 and'I'I. Andcthe. sameis true ofanyzof the remaining nine. select -fingerson the .bar I4 which: corresponds:v `to "1 operate Y andhold bars occupying theirqnormal positions. Next the energizingscircuit ofthe operate snag-4 net I6 is closed, and thisfmagnet pulls. the idravva bar I1 downwardly against the'tension'of spring 59. The downward movement of .the.bar.. I1 acts through the links 18, 19,. toimpartia :sliding: movement to the ten :operate :bars .54;1 58,'corree sponding to the No. O'units-rows vvoffoontacts .in

the respective tens groups.' Since,` however, only...`

one of the ten select magnets I I; I5, is operated 13, 80, are in vertical registration .with the cor+ responding select `fingers 16,. 8 I.. Sinceghowever; the select magnet 6 vis. theonlyroperated one-in"l the group ofV ten, the corresponding `finger f1'is'.

the only one that has beentensioned.downwardly.

Therefore, as soon as the bar 1II is :advanced bythe operatef bar .58, the tensioned select finger-10.enters the f notch 13 and at the same .time enters .the'notchf' 82 in 4.the off-normal bar 83,' the latter notch'. being normally in registration withthe finger 16.'l

Finally the magnet I8 is deenergized followed; bythe deenergizationof magnets-I 5 andi.; Upon the deenergization of magnet i I6 the. fspringsiif restores thebar I1 andthe associcfitedoperate bars 54, 58. The restoration ofthe operate-bar 58'removes the operating'forcefrom `the-.heidiv bar 1I, and this bar is returnedto.normal-:byvv

against the edge of the bar'1l.

its retractile spring Sill. As. the :bar )1I returns to normal under the force ofthefspring 84'," the.;` positioned select finger lil'is movedv .toftheiright to operate and close the Contact springswtthe`l desired set 68.1 Moreover,the m'ovementvo'f '.the bar `1I imparts a similar. movementtoithe fotinormal bar 83,A through the. medium of thelnr..

ger 10,V and the olif-normaliy bar. 83 vclo'sf-:sthe' asso@ .pedienty is avoidedinthe switch disclosed herein. by providing the off-normal bar above describedv for yoperating thel ofi-normal contact set When-.-

ciated yoff-normal springsl 85.

The` restoration- Y of the magnet I5 and the bar.` I4apermitstthez-i select ngers 14, 15, to lreturnto their normal:

positions, and thus the operate andholdibais 58 and 1I -areuncoupled Tlierestoration-nof1'- the select bar 5, which occursv slightly following the Vreturn movement of the hold :bar \1I, .also permits al1 of its'select. iingers` 3I,..i9, etc: .to

return to their normal positionsnivithpthe feX-V ception of the finger. "III, whichis nowiheld infits flexed and .contact-.closing :position by' the re. stored hold bar 1 I.

bar 5, the edge of the notch 13 inthe hold-bar 1I is under-cut slightly as'. illustrated yin the- And the same is true of the remain-.-A

To insureI that .the finger: 16 is trapped and'held 4after the restoration of the. i

gized: and are :not A'required thereafter-to mainftainttheaselectedfsetl ofcontacts .in itsrfoper.- atedcondition: In asimilari manner any-desired andfioperated-ito .the exclusion'4 ofssall` other fsets, ontwmor .more sets ofcontacts may be selected'.-

Wardly, causing .the select -nger 14 `.to enter. the notches f16-and-f11: The momentaryenergization of -magnet'- I6,A which Aoccurs-shortly thereafter,Vv

causes the sliding movement ofthe holdbar. 1I f against the tension of the retraotil'espringv84. As soon as :the hold bar 1I -has advanced sufliciently .the trapped select finger. '.1 Il .escapes the underfcut edge -;of- .the I notch V'lwand-I returns `to its normal .position,-permitting:the contacts 468 to open.' Moreover; the. momentary movement'f of the bar1I andthefrestorationof the'nger 1I]y v releases `the 'off-normal bar 83 rand thewass'o-'f ciated off -normal contacts 85.

Although not 4sc-tillustratedin the drawings, it willbe understoodthat separate retractile springs may vbe-provided for eachof. the oli-normal barsy.

or the ofi-normal. springs .f themselves may furnishfthe restoringforce.

Theseeoi-.norrnalcontact. springs, associated I with the -hold=bars of-the switch, are sometimes required for circuit reasonssa For example, it has .been the practice v'heretofore to use f the conventional crossbar switch as aline switch, infwhich case the OIT-normal contact springs may serve as thecut-oiT contacts forH the subscribers line. Moreover, the operation of the. conventionalv switchis such that these oli-normalA springs may be operated. directly` from. .the hold bar, which is moved Toits operated position-and maintained insuch position throughout A.the connection.. Inthe switch. disclosed herein,-A however, the vhold bars are normally in their contact-actuating position. and also occupy Lthis same Yposition during.. Thereforeythe dithe contact .closure `periodsf rect. movement .of..the-hold bar cannot be utilized to close andmaintain Aclosedthe associated While it would be possible'to secure the equivalent of an off-normal contact set at each cross-point, this would in.-

crease the size andcost .of-the switch andvwould be impractical in other respects. Such an exever. one ofthe associated sets of switching con` tacts is operated.

It. will be noted .that the switch is not limited described. If .desired the magnets Band-'I5 .may be :operated-simultaneously, followedby the op eration 'of magnet I6, orv thernagnet I5 maybe operated first, followedby the operation ofmage netv 6,- followed'in turn by the operationuomag In either fcase the result is the same:v namely the lselection and closure 'of the desired'.

set of contacts 68;

A. betterv understanding of `the assumed Anumbering'planl may be had from Fig.- 3.V This gure illustrates the ten fhundreds group of contacts ar.

ranged .in ten..vertical-rows.y -Four :of thesefvertical rows 86, 81, 86, 89 are shown, the No. 0, No. 1, No. 8 and No. 9 hundreds groups. The

select magnets-sand. Fanzoperate :magnet-g follow.` 1 ing i.,ivhichialltthree of the magnets rare'.y deener-,

tenhundreds rows are also divided horizontally into ten tens groups, the groups 1, 3, 9 illustrated being the No. 0, No. 4 and No. 9 tens groups and corresponding to those shown in Fig. l. The units values of the ten sets of contacts in each tens group are assigned in order beginning at the bottom of the group. For example, the first ten sets in the No. hundred, namely the ten sets comprising the No. 0 tens group 1, are numbered from 0 to 9 beginning at the bottom of the group. Inspection of the ligure will show that this same numbering arrangement prevails throughout the complete group of a thousand contact sets. It should be understood, however, that any suitable numbering arrangement may be applied to the switch structure shown and described herein.

What is claimed is: 1. The combination in a switching device of a plurality of switching groups of separately-operindividual respectively to the rows of actuating" elements in a first coordinate direction, first select magnets individual respectively to the rows of actuating elements in the second coordinate direction, each of said rows in the second coordinate direction comprising actuating elements in all of said switching groups, the energization of any one of said first select magnets serving to prepare the associated actuating elements, second select magnets individual respectively to said switching groups, the energization of any one of said second select magnets serving to Iselect for operation all of the bars associated with the corresponding switching group, operate magnets, each serving a bar for each of said switching groups, the energization of any operate magnet in conjunction with said select magnets serving to move a particular bar of the selected switching group into operative relation with the corresponding prepared actuating element, and

means acting on said bar for returning it to its normal position when said operate magnet is deenergized, said bar on its return movement acting upon the prepared actuating element to operate the associated set of contacts.

2. The combination in a switching device of a plurality of crossbar switch units each including a plurality of separately-operable sets of contacts, Contact actuating elements individual respectively to said contact sets, said contact sets and actuating elements being arranged in horizontal and vertical rows, hold bars individual respectively to the horizontal rows of actuating elements, nrst select magnets individual respectively to the vertical rows of actuating elements, each of said vertical rows comprising actuating elements in all of said switch units, the energization of any one of said first select magnets serving to prepare the associated actuating elements, second select magnets individual respectively to said switch units, the energization of any one of said second select magnets serving to prepare the hold bars of all of the horizontal rows of the corresponding switch unit, operate magnets, each serving a hold bar for each of said switch units, the energization of any operate magnet in conjunction with said select magnets serving to move a particular one of the prepared hold bars into operative relation with the correspondingV prepared actuating elements, and

means acting on said hold bar for returning it. to its normal position when said operate mag--` net is deenergized, said hold bar on its return movement acting upon the prepared actuating element to operate the associated set of contacts 1 and to maintain said contacts in an operated condition following the deenergizaton of said select and operate magnets.

3. The combination in a switching device of a plurality of crossbar switch units, each unit having a plurality of separately-operable sets of contacts, contact actuating fingers individual respectively to said Contact sets, said contact sets and actuating fingers being arranged in horizontal and vertical rows, hold bars individual respectively to the horizontal rows of actuating fingers, each hold bar having notches for engagement by the respective fingers in the horizontal row, first select magnets individual respectively to the vertical rows of actuating fingers, the energization of any one of said Iirst'select magnets serving to move in all of said switch units the actuating fingers of the corresponding vertical row into prepared positions with respect to the corresponding hold bars, second select magnets individual respectively to said switch units, the energization of any one of said second select magnets serving to prepare for operation all of the hold bars associated with the corresponding switch unit, operate magnets each serving a hold bar for each of said switch units, the energization of any operate magnet in conjunction with said select magnets serving to move a particular one ci the prepared hold bars into a position where the prepared actuating finger engages the associated notch thereof, and retractile means acting on said hold bar for returning it to its normal position when said operate magnet is deenergized, said hold bar on its return movement acting upon the linger engaging the notch therein to operate the associated ser; of contacts and to maintain them operated after the release of said select and operate magnets, the reoperation of said hold bar by the associated operate magnet' serving to restore the operated set of contacts to their normal condition.

4. The combination in a switching device of a plurality of separately-operable contact sets, contact actuating elements individual respectively to said contact sets, said contact sets and actuating elements being arranged in coordinate rows, select bars individual respectively to the rows of actuating elements in one coordinate direction,

hold bars individual respectively to the rows of actuating elements in the other coordinate direction, olf-normal contact sets, one for each of said hold bars, oil-normal bars individual respectively to said oli-normal Contact sets and operatively associated with corresponding hold bars, means for operating any one of said select bars to move each one of the associated actuating elements into operative relation with respect to-l the associated hold `bar and oli-normal bar, and

means for operating any one of said hold barsv to move the positioned actuating element andv the contacts of the associated set into their closed position, the movement of said actuating element serving to move the associated oli-normal bar to close the corresponding set of off-normal contacts.

WILLIAM H. T. HOLDEN. 

